title: The effect of surfactant and suspending agent concentration on the effective particle size of metered-dose inhalers.
abstract: The aim of this study was to examine the influence of the concentrations of surfactant and suspending agent on the quantity of effective particles (size < 10 microm) delivered by metered-dose inhalers. A 2-factor, 3-level, face-centred central composite design was used to construct a second-order polynomial model which describes the effect of formulation factors (suspending agent, surface-active ingredient) on the therapeutically important characteristic (effective particle size) delivered by metered-dose inhalers. Oleic acid was selected as the surface-active ingredient, and the suspending agent was anhydrous alcohol. A non-linear model demonstrated with good correlation the effect of the amounts of surfactant and suspending agent on the quantity of particles of effective size. The results obtained enable determination of the correct amount of surface-active ingredient and the optimum quantity of the suspending agent, thus enabling formulation of a therapeutically effective formulation.
authors.affiliation: EGIS Pharmaceuticals Ltd, Budapest, Hungary.
authors.forename: L T
authors.initials: LT
authors.lastname: Fedina
authors.forename: R
authors.initials: R
authors.lastname: Zelkó
authors.forename: L I
authors.initials: LI
authors.lastname: Fedina
authors.forename: Z S
authors.initials: ZS
authors.lastname: Szabados
authors.forename: M
authors.initials: M
authors.lastname: Szántó
authors.forename: G
authors.initials: G
authors.lastname: Vakulya
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003198:Computer Simulation; D016001:Confidence Intervals; D000431:Ethanol / Q000737:chemistry; D005079:Excipients / Q000737:chemistry*; D009330:Nebulizers and Vaporizers; D017711:Nonlinear Dynamics; D019301:Oleic Acid / Q000737:chemistry; D010316:Particle Size; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D005079:Excipients; D013501:Surface-Active Agents; D019301:Oleic Acid; D000431:Ethanol